This set of Engineering Physics Multiple Choice Questions & Answers (MCQs) focuses on “Dimensional Analysis”.
1. What is the science that deals with every substance, its structure, its composition and changes?
a) Botanical science
b) Zoological science
Explanation: Chemistry is the science that deals with every substance, its structure, its composition and changes. Physics is the study of the natural world, matter, energy and radiation, while biology is the science that deals with the behaviour of living things are called biological sciences.
2. Quantum physics deals with macroscopic phenomena.
Explanation: Classical physics deals with macroscopic phenomena which may be at the laboratory, terrestrial and astronomical. Quantum physics deals with microscopic phenomena at the minute scales of atoms.
3. Which of the following uses electromagnetic waves?
c) Detecting fractures
d) Electric motors
Explanation: Electromagnetic waves are used in the radio. While radiotherapy and detecting fractures are done by x-rays and electric motor comes under the electric appliance.
4. Which is the universal attractive force?
a) Electromagnetic force
b) Strong nuclear force
c) Weak nuclear force
d) Gravitational force
Explanation: Gravitational force is the force of mutual attraction between two bodies by virtue of their masses. Every body attracts every other body in the universe with this force. Hence it is the universal attractive force.
5. Gravitational force is the weakest force in nature.
Explanation: Gravitational force is the weakest force in nature because it cannot be felt by us on daily basis. Electromagnetic force is the strongest force in nature.
6. Which of the following is an example of electromagnetic force?
a) Motion of moon around earth
b) Evolution of stars
c) Evolution of galaxies
d) Compression of spring
Explanation: When a spring is compressed, it exerts a force of elasticity due to the net repulsion/ attraction between the neighbouring atoms. This net repulsion or attraction is the sum of the electrostatic forces between the electrons and nuclei of the atoms.
7. Why is climbing a lamp post harder than climbing up a tree?
a) Because of parallel friction force
b) Because of contact force between the bodies
c) Because of Van der Wall’s force
d) Because of rope force
Explanation: Sometimes, the electromagnetic contact force between two bodies may have a component acting parallel to the surface of contact. This is called friction. When bodies are placed with their smooth surfaces in contact, they provide only a small parallel component of contact of force and hence friction between them is small. This is why climbing a metallic lamp post is difficult than climbing up a tree.
8. Gravitational force, despite being a weak force, governs the large scale motion.
Explanation: Mass is only of one type. So the gravitational force is always attractive. Between two neutral objects, the gravitational force goes on adding over all pairs of particles of the two objects while the electromagnetic forces being equally attractive and repulsive, add up to zero. That is why large scale motion in the universe is controlled by the weakest gravitational force.
9. When a body is falling freely under gravity, the total mechanical energy remains constant because of which of the following?
a) Law of conservation of energy
b) Unification of force
c) Electromagnetic force
Explanation: According to the law of conservation of energy, energy can neither be created nor can it be destroyed but it can be changed from one form to another. When a body falls freely, under gravity, its potential energy gradually changes into kinetic energy. But its total mechanical energy remains constant at any point of its motion.
10. What happens when a bullet is fired from a rifle?
a) The rifle becomes weightless
b) We fall back
c) Rifle gives backward kick
d) Bullet doesn’t leave the rifle
Explanation: A rifle gives a backward kick on firing a bullet. Before firing, both the bullet and rifle are at rest and the initial momentum of the system is zero. As soon as the bullet is fired, it moves forward with a large velocity. In order to conserve momentum, the rifle moves backward with such a velocity that the final momentum of the system is zero.
Sanfoundry Global Education & Learning Series – Engineering Physics.
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